spine : The outer portion of a book which covers the actual binding. The spine usually faces outward when a book is placed on a shelf. Also known as the back.

cocked : Refers to a state where the spine of a book is lightly "twisted" in such a way that the front and rear boards of a book do not align when the book is lying flat. Severity may differ.

Ex-library : A former library book, generally containing library acquisition and ownership stamped markings, and other typical indications of the library's use.

8vo : Short for Octavo, A book whose page size is approximately 8-10 inches tall. The size is based on a sheet of paper 25 inches by 38 inches, the size of paper traditionally used by book printers, which has been folded and cut into 16 pages.. Unfortunately often misunderstood to mean 8 volumes.